Four New Species of Harringtonia: Unravelling the Laurel Wilt Fungal Genus

Abstract

Symbiosis between beetles and fungi arose multiple times during the evolution of both organisms. Some of the most biologically diverse and economically important are mutualisms in which the beetles cultivate and feed on fungi. Among these are bark beetles and Harringtonia, a fungal genus that produces Raffaelea-like asexual morph and hosts the causal agent of laurel wilt, H. lauricola (formerly Raffaelea lauricola). In this study, we propose four new species of Harringtonia associated with beetles from Belize and Florida (USA). We hope to contribute towards a more robust and inclusive phylogenetic framework for future studies on these beetle-fungi relationships and their potential impact in crops and forests worldwide.

Correction to: Symbiotic Fungi Associated With Xyleborine Ambrosia Beetles (Coleoptera: Curculionidae: Scolytinae) and the Imperative of Global Collaboration

“…Modern ambrosia research has continued to reveal the varied range of relationships shared between xyleborine ambrosia beetles and fungi (Kostovcik et al 2015, Skelton et al 2018. This includes the identification of many previously unknown fungal symbionts (von Arx and Hennebert 1965;Harrington et al 2008Harrington et al , 2014Freeman et al 2013;Li et al 2016;Lynch et al 2016;Simmons et al 2016aSimmons et al , 2016bAoki et al 2018Aoki et al , 20192021;Lynn et al 2020;Mayers et al 2020aMayers et al , 2020bAraújo et al 2022) and recognition that the same species of ambrosia fungus might grow in the galleries of non-xyleborine beetles as well as those of xyleborines (Gebhardt et al 2004). Since the discovery and identification of the mycangium (Francke-Grosmann 1956, Schedl 1962, Batra 1963, research has revealed the central role this organ plays in the development and maintenance of ambrosia symbioses (Mayers et al 2022).…”

“…De Beer et al ( 2022) recently described the new genus Harringtonia to accommodate three former Raffaelea species: Raffaelea aguacate Simmons, Dreaden and, Ploetz, Raffaelea brunnea Batra (associated with Corthylini ambrosia beetles), and Raffaelea lauricola Harrington Fraedrich and Aghayeva, the causal agent of laurel wilt (Fraedrich et al 2008. Only H. lauricola is a pathogen, while other Harringtonia species appear harmless (Araújo et al 2022). Harringtonia ambrosioides Araújo, Li, and Hulcr was recently described after being isolated from the Neotropical xyleborine Dryocoetoides capucinus (Eichhoff) (Araújo et al 2022).…”

“…Only H. lauricola is a pathogen, while other Harringtonia species appear harmless (Araújo et al 2022). Harringtonia ambrosioides Araújo, Li, and Hulcr was recently described after being isolated from the Neotropical xyleborine Dryocoetoides capucinus (Eichhoff) (Araújo et al 2022). Harringtonia lauricola quickly spreads throughout its tree host after inoculation and can prevent water transport by blocking the xylem, causing wilt symptoms within 14 days (Inch et al 2012).…”

“…Most scientific attention has been focused on invasive xyleborines, especially those that vector pathogenic fungi (e.g., Norris 1979, LaBonte et al 2005, Galko et al 2018, Schiefer 2018, Rabaglia et al 2019, Salman et al 2019, Carrillo et al 2020a, Faccoli 2021 or cause other significant damage in North America and Europe. Some knowledge gained from these investigations focuses on the identities of ambrosia fungi (Harrington et al 2008;Freeman et al 2013;Lynch et al 2016;Simmons et al 2016aSimmons et al , 2016bAoki et al 2018Aoki et al , 2019Aoki et al , 2021Araújo et al 2022). However, despite considerable historical discourse regarding the classification of ambrosia fungi (see Leach et al 1940, Francke-Grosmann 1967, Araújo et al 2022, de Beer 2022, the identities of most xyleborine ambrosia fungi are poorly understood or unknown.…”

“…Some knowledge gained from these investigations focuses on the identities of ambrosia fungi (Harrington et al 2008;Freeman et al 2013;Lynch et al 2016;Simmons et al 2016aSimmons et al , 2016bAoki et al 2018Aoki et al , 2019Aoki et al , 2021Araújo et al 2022). However, despite considerable historical discourse regarding the classification of ambrosia fungi (see Leach et al 1940, Francke-Grosmann 1967, Araújo et al 2022, de Beer 2022, the identities of most xyleborine ambrosia fungi are poorly understood or unknown. Nevertheless, the considerable attention given to invasive species has produced a foundational understanding of the mechanistics and ecology of invading populations (Storer et al 2017, Dzurenko et al 2021, Morales-Rodriguez et al 2021, Urvois et al 2022) and the evolution of fungus farming in beetles (Farrell et al 2001, Biedermann and Vega 2020)…”